The effects of the brain's fissures on the electroencephalogram (EEG) and magnetoencephalogram (MEG) and on the localization of electrical sources in the brain using these measurements would be determined. Comparisons of the effects on the two types of measurements would be made. This research would provide the first accurate, detailed data about these effects. The data are required to improve the accuracy of localization methods. Accurate localization of sources in the brain is important in diagnosis and treatment of brain disorders and in brain research. This research would be performed using computer models of the brain and head. The models would range from simple spherical ones to more realistic ones based on accurate anatomical data. The effects of the fissures on EEG's and MEG's would be determined by comparing such data from models with a fissure with data from models having no fissures. The effects of the fissures on localization would be determined by using data from a head model with a fissure to calculate a source location in a model without fissures.